Lithographic apparatus and device manufacturing method

Abstract

A lithographic apparatus includes an illumination system including a field faceted mirror including a plurality of field facets and configured to receive radiation from a radiation source and form a plurality of images of the radiation source on corresponding pupil facets of a pupil faceted mirror. Each of the field facets is configured to provide an illumination slit at a level of a patterning device. The illumination slits are summed together at the level of the patterning device to illuminate the patterning device. First blades are configured to block radiation from a radiation source and each first blade is selectively actuable to cover a portion of a selectable number of field facets. The field faceted mirror further comprises partial field facets, the partial field facets being configured to produce a partial illumination slit at the level of the patterning device, and the pupil faceted mirror further includes pupil facets corresponding to the partial field facets. The partial field facets are configured to produce an illumination slit that is summed with the summed illumination slits of the field facets and/or correct for non-uniformity in the summed illumination slits of the field facets. Second blades are selectively actuable to cover a portion of a selectable number of partial field facets.

1. A lithographic projection apparatus, comprising:
 an illumination system configured to condition a beam of radiation; 
 a support configured to support a patterning device, the patterning device configured to pattern the beam of radiation according to a desired pattern; 
 a substrate table configured to hold a substrate; and 
 a projection system configured to project the patterned beam of radiation onto a target portion of the substrate, 
 wherein the illumination system comprises a field faceted mirror comprising a plurality of field facets and configured to receive radiation from a radiation source and form a plurality of images of the radiation source on corresponding pupil facets of a pupil faceted mirror, each of the field facets being configured to provide an illumination slit at a level of the patterning device, the illumination slits being summed and superimposed together at the level of the patterning device to illuminate the patterning device; and a first blade configured to block radiation from the radiation source, the first blade being selectively actuable to cover a portion of a selectable number of field facets. 
 
   
   
     2. An apparatus according to  claim 1 , wherein the field faceted mirror further comprises partial field facets, the partial field facets being configured to produce a partial illumination slit at the level of the patterning device, and the pupil faceted mirror further comprises pupil facets corresponding to the partial field facets. 
   
   
     3. An apparatus according to  claim 2 , wherein the partial field facets are configured to produce an illumination slit at the level of the patterning device that is summed with the summed illumination slits of the field facets. 
   
   
     4. An apparatus according to  claim 2 , wherein the partial field facets are configured to correct for non-uniformity in the summed illumination slits of the field facets. 
   
   
     5. An apparatus according to  claim 2 , wherein the partial field facets comprise a pair of identical partial field facets configured to be symmetrical in a pupil plane of the pupil faceted mirror. 
   
   
     6. An apparatus according to  claim 2 , further comprising a second blade configured to block radiation from the radiation source, the second blade being selectively actuable to cover a portion of a selectable number of partial field facets. 
   
   
     7. A device manufacturing method, comprising:
 providing a beam of radiation using an illumination system; 
 patterning the beam of radiation with a pattern in its cross-section; 
 projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material at least partially covering a substrate, wherein the illumination system comprises a field faceted mirror comprising a plurality of field facets and configured to receive radiation from a radiation source and form a plurality of images of the radiation source on corresponding pupil facets of a pupil faceted mirror, each of the field facets being configured to provide an illumination slit at a level of a patterning device configured to pattern the beam of radiation, the illumination slits being summed and superimposed together at the level of the patterning device to illuminate the patterning device, and a first blade configured to block radiation from the radiation source, the first blade being selectively actuable to cover a portion of a selectable number of field facets. 
 
   
   
     8. A method according to  claim 7 , wherein the field faceted mirror further comprises partial field facets, the partial field facets being configured to produce a partial illumination slit at the level of the patterning device, and the pupil faceted mirror further comprises pupil facets corresponding to the partial field facets. 
   
   
     9. A method according to  claim 8 , wherein the partial field facets are configured to produce an illumination slit at the level of the patterning device that is summed with the summed illumination slits of the field facets. 
   
   
     10. A method according to  claim 8 , wherein the partial field facets are configured to correct for non-uniformity in the summed illumination slits of the field facets. 
   
   
     11. A method according to  claim 8 , wherein the partial field facets comprise a pair of identical partial field facets configured to be symmetrical in a pupil plane of the pupil faceted mirror. 
   
   
     12. A method according to  claim 8 , further comprising a second blade configured to block radiation from the radiation source, the second blade being selectively actuable to cover a portion of a selectable number of partial field facets. 
   
   
     13. An apparatus according to  claim 1 , wherein the first blade is selectively actuable to cover a portion of a plurality of field facets. 
   
   
     14. An apparatus according to  claim 1 , comprising a plurality of first blades, each first blade selectively actuable to cover a portion of a plurality of field facets. 
   
   
     15. An apparatus according to  claim 2 , wherein the partial field facets are configured to produce the illumination slit at the level of the patterning device when combined. 
   
   
     16. An apparatus according to  claim 6 , wherein the second blade is selectively actuable to cover a portion of a single partial field facet. 
   
   
     17. An apparatus according to  claim 6 , comprising a plurality of second blades, each second blade selectively actuable to cover a portion of a respective single partial field facet. 
   
   
     18. A method according to  claim 7 , wherein the first blade is selectively actuable to cover a portion of a plurality of field facets. 
   
   
     19. A method according to  claim 8 , wherein the partial field facets are configured to produce the illumination slit at the level of the patterning device when combined. 
   
   
     20. A method according to  claim 12 , wherein the second blade is selectively actuable to cover a portion of a single partial field facet.